Non-Linear Transformer with Improved Construction and Method of Manufacturing the Same

Abstract

A three-phase non-linear transformer and a method of constructing the same. The non-linear transformer includes a non-linear ferromagnetic core having a plurality of frames, each of which has a closed or substantially closed periphery. The frames are arranged to form at least three legs. A low voltage winding is formed around each leg and a high voltage winding is formed around each low voltage winding. Each high voltage winding includes a plurality of serially-connected disc windings. Each of the disc windings is formed of alternating concentric layers of a conductor strip and an insulation strip, wherein the conductor strip having a width to thickness ratio of greater than 10:1. A casing encapsulates each pair of high voltage and low voltage windings. The casing is formed using a mold at least partially formed by a winding device used to wind the high voltage and low voltage windings.

1 . A three-phase non-linear transformer, comprising:
 a ferromagnetic core having three or more legs arranged in a non-linear configuration;   coil assemblies mounted to the legs, respectively, each of the coil assemblies comprising:
 a low voltage winding; and 
 a high voltage winding comprising a plurality of serially-connected disc windings, each of the disc windings comprising alternating concentric layers of one or more conductor strips and one or more insulation strips, each conductor strip having a width to thickness ratio of greater than 10:1; and 
 a casing encapsulating the high voltage winding, the casing comprising a dielectric polymeric material. 
   
     
     
         2 . The non-linear transformer of  claim 1 , wherein the legs of the core are arranged in a triangular configuration. 
     
     
         3 . The non-linear transformer of  claim 2 , wherein the core comprises three frames, each having a closed or substantially closed periphery. 
     
     
         4 . The non-linear transformer of  claim 3 , wherein each of the frames has a rounded rectangular shape has a pair of leg sections joined by shoulders to a pair of yoke sections, respectively. 
     
     
         5 . The non-linear transformer of  claim 4 , wherein the frames are arranged in a triangular configuration such that the leg sections of each frame abut leg sections of the other two frames, respectively, thereby forming the three legs. 
     
     
         6 . The non-linear transformer of  claim 1 , wherein each conductor strip is comprised of copper or aluminum. 
     
     
         7 . The non-linear transformer of  claim 1 , wherein the disc windings of each high voltage winding are formed from a single length of conductor strip. 
     
     
         8 . The non-linear transformer of  claim 1 , wherein each conductor strip is comprised of copper or aluminum and has a width to thickness ratio of from about 400:1 to about 10:1. 
     
     
         9 . The non-linear transformer of  claim 1 , wherein the dielectric polymeric material is an epoxy. 
     
     
         10 . The non-linear transformer of  claim 9 , wherein the dielectric polymeric material is a cycloaliphatic epoxy. 
     
     
         11 . The non-linear transformer of  claim 1 , wherein the low voltage winding is encapsulated in a casing comprising a dielectric polymeric material. 
     
     
         12 . The non-linear transformer of  claim 1 , wherein the low voltage winding comprises an insulated conductor with a rectangular cross-section. 
     
     
         13 . A method of constructing a three-phase non-linear transformer, comprising:
 (a.) providing a non-linear ferromagnetic core comprising a plurality of frames, each of which has a closed or substantially closed periphery, the frames being arranged to form at least three legs;   (b.) for each leg of the core, forming a low voltage winding around the leg;   (c.) forming a high voltage winding around each low voltage winding, wherein the forming of each high voltage winding around its associated low voltage winding comprises:
 providing one or more insulation strips; 
 providing one or more conductor strips, each having a width to thickness ratio of greater than 10:1; 
 winding the one or more insulation strips and the one or more conductor strips around the low voltage winding to form a plurality of disc windings arranged in an axial direction of the low voltage winding, wherein each of the disc windings comprises alternating concentric layers of the one or more insulation strips and the one or more conductor strips; and 
   (d.) casting each high voltage winding in a dielectric polymeric material.   
     
     
         14 . The method of  claim 13 , wherein the step of winding the one or more insulation strips and the step of winding the one or more conductor strips are performed simultaneously. 
     
     
         15 . The method of  claim 14 , wherein the one or more insulation strips and the one or more conductor strips are secured together before the one or more insulation strips and the one or more conductor strips are wound around the low voltage coil. 
     
     
         16 . The method of  claim 13 , wherein for each leg, the step of forming the low voltage winding comprises:
 providing an insulation sheet;   providing a conductor sheet; and   winding the insulation sheet and the conductor sheet around the leg to form alternating concentric layers of the insulation sheet and the conductor sheet.   
     
     
         17 . The method of  claim 13 , wherein each conductor strip is comprised of copper or aluminum. 
     
     
         18 . The method of  claim 13 , wherein the disc windings of each high voltage winding are formed from a single length of conductor strip. 
     
     
         19 . The method of  claim 13 , wherein each conductor strip is comprised of copper or aluminum and has a width to thickness ratio of from about 400:1 to about 10:1. 
     
     
         20 . The method of  claim 13 , further comprising casting each low voltage winding in a dielectric polymeric material. 
     
     
         21 . The method of  claim 13 , wherein for each leg, the step of forming the low voltage winding comprises:
 providing an insulated conductor with rectangular cross-section; and   winding the conductor around the leg to form one or more concentric layers of the conductor.